METHOD OF MANUFACTURING SEMICONDUCTOR DEVICES AND CORRESPONDING SEMICONDUCTOR DEVICE
Semiconductor chips are arranged on a first surface of a common electrically conductive substrate having an opposite second surface. The substrate includes adjacent substrate portions having mutually facing sides with sacrificial connecting bars extending between adjacent mutually facing sides. A solderable metallic layer is present on the second surface extending over the sacrificial connecting bars. The solderable metallic layer is selectively removed (by laser ablation or etching, for example) from at least part of the length the sacrificial connecting bars. The common electrically conductive substrate is then cut along the length of the elongate sacrificial connecting bars to provide singulated individual semiconductor devices. Undesired formation of electrically conductive filaments or flakes bridging parts of the substrate intended to be mutually isolated is countered.
1 . A method, comprising:
arranging a plurality of semiconductor dice onto a first surface of a common electrically conductive substrate, wherein the common substrate has a second surface opposite the first surface and comprises adjacent substrate portions having mutually facing sides with elongate sacrificial connecting bars extending between adjacent mutually facing sides, with a solderable metallic layer on the second surface of the common electrically conductive substrate and the solderable metallic layer extending over the connecting bars;
removing the solderable metallic layer from at least part of the length the elongate sacrificial connecting bars; and
cutting the common electrically conductive substrate having the plurality of semiconductor dice arranged onto the first surface thereof to provide singulated individual semiconductor devices, wherein cutting is made along a length of the elongate sacrificial connecting bars having the solderable metallic layer removed from at least part of the length the sacrificial connecting bars.
2 . The method of claim 1 , wherein the solderable metallic layer comprises tin.
3 . The method of claim 1 , further comprising providing the solderable metallic layer on the second surface of the common electrically conductive substrate via plating.
4 . The method of claim 1 , wherein removing the solderable metallic layer is performed using laser ablation.
5 . The method of claim 1 , wherein removing the solderable metallic layer is performed using selective etching.
6 . The method of claim 1 , wherein removing the solderable metallic layer comprises removing at selected locations distributed along the length the elongate sacrificial connecting bars.
7 . The method of claim 1 , wherein removing the solderable metallic layer comprises removing the solderable metallic layer from the elongate sacrificial connecting bars at tie bars coupling the elongate sacrificial connecting bars to adjacent substrate portions in the common electrically conductive substrate.
8 . The method of claim 1 , wherein removing the solderable metallic layer comprises removing the solderable metallic layer from distal ends of the tie bars coupling the elongate sacrificial connecting bars to adjacent substrate portions in the common electrically conductive substrate.
9 . A semiconductor device obtained by the method of claim 1 .
10 . A method, comprising:
coating a back surface of a leadframe including leads coupled to a sacrificial connecting bar with a solderable metallic layer;
removing the solderable metallic layer from the back surface of the sacrificial connecting bar at selected locations; and
cutting the leadframe along a length of the sacrificial connecting bar.
11 . The method of claim 10 , wherein the solderable metallic layer comprises tin.
12 . The method of claim 10 , wherein removing the solderable metallic layer is performed using laser ablation at the selected locations.
13 . The method of claim 10 , wherein removing the solderable metallic layer is performed using selective etching at the selected locations.
14 . The method of claim 10 , wherein the selected locations are distributed along the length the sacrificial connecting bar.
15 . The method of claim 10 , wherein the leads are coupled to the sacrificial connecting bar by tie bars, and wherein the selected locations are locations at said tie bars.
16 . A semiconductor device obtained by the method of claim 10 .
17 . A semiconductor device, comprising:
at least one semiconductor die arranged onto a first surface of a portion of an electrically conductive substrate having a second surface opposite the first surface;
wherein the portion of electrically conductive substrate comprises remainders of tie bars;
wherein the electrically conductive substrate includes leads coupled to said remainders of tie bars; and
a solderable metallic layer present on the second surface of electrically conductive substrate except at said remainders of tie bars.